This invention relates generally to aircraft guidance and navigation, and more particularly relates to a system and method for safely disabling manual aircraft navigation or direction to avoid intentional or unintentional dangerous misdirection of the aircraft.
On Sep. 11, 2001, the World trade center in New York, N.Y. became the object of a terrorist attack of previously unimaginable proportions. The terrorist attack utilized a simple scheme of misdirecting commercial aircraft such that the aircraft struck the twin towers of the world trade center destroying both buildings, surrounding buildings, and the aircraft themselves. The exact death toll of the attack is not currently known and may never be precisely determined due the degree of disintegration of the planes, buildings, and victims. However, it is known that at least several thousand innocent people, both passengers of the misdirected airplanes as well as occupants of the targeted building, were killed.
The financial impact of such attacks, while easily ignored in light of the great loss of life, are staggering. The sources of such loss are the material loss of structures and equipment likely to be borne by insurers, the loss of business revenue for businesses located in the affected area, the national economic inefficiencies caused as people nationwide are distracted and frightened by the attack, and the loss of revenue to airlines as frightened passengers turn to other modes of travel. There will also be litigation-related losses as affected individuals and organizations seek redress for a perceived wrongful loss of life, property, or revenue.
Simply put, this new form of attack greatly raises the potential human and economic loss that may be caused by terrorist organizations. There are many ways to attempt to minimize the casualties of such attacks. Some current efforts focus on minimizing the volume and flammability of the jet fuel that is often violently released and dispersed in collisions involving one or more aircraft. Other efforts are directed at security precautions to prevent in the first instance the introduction of weapons or explosives onto an aircraft.
Neither of these solutions is optimal, for the first fails to save the aircraft passengers themselves, while the second cannot be completely successful at detecting and stopping the passage of all weapons without great expense of time and money, and additionally fails to deter terrorist attacks carried out by purely physical strength against weaker passengers and aircraft personnel.
Other methods and systems of deterring hijacking of aircraft have been devised and attempted with varying degrees of success, but as the attack of September 11 shows, none have attained complete success.
In summary, the invention has several variations and solves the shortcomings inherent in prior systems. The primary embodiment allows a pilot or other person to trigger an aircraft security mode from within the aircraft such as by pressing a button located in the cockpit of the aircraft. The result of the entry of the aircraft into security mode is that manual navigation of the aircraft from within the cockpit is rendered impossible; the control surfaces, throttle settings, and all other aircraft navigational functions are carried out automatically from this point in time forward.
In an embodiment, the pilot or other authorized personnel may posses an override code usable to restore the ability to manually control the aircraft, in order to regain control after an accidental triggering of the security mode. There are hazards associated with allowing override. For instance, a hijacker may force the appropriate person to divulge the code.
Once in security mode, a navigation module selects a nearest landing facility from a digital database of facilities based on position sensor information and other factors, after which it utilizes the computerized navigation facilities of the aircraft to redirect the aircraft toward that facility. Approach, landing, and roll out are executed automatically by the module utilizing the computerized navigation facilities of the aircraft. In an embodiment, the module causes a signal to be transmitted to ground personnel at the selected landing facility, so that the approach path may be cleared.
In another embodiment of the invention, the guidance module periodically accesses a database of terrain features, the terrain features being identified by at least their location and altitude. The module compares the location and altitude of the features represented in the database with the aircraft""s present location, altitude and other data based on sensor information such as altimeter and GPS readings. If the aircraft""s heading, velocity, altitude and location indicate an imminent terrain collision, the module temporarily disables manual navigation of the aircraft in order to place the craft into a collision avoidance route.
The terrain features represented in the database may be earth features such as mountains, cliffs, etc., and also preferably include significant man-made structures such as stadiums, office buildings, and so on. In one further embodiment, the terrain features include groups or clusters. For example, a city could be represented in the database as a single feature having constant or preferably spatially varying altitude corresponding to the collective physical extent of the various structures of the city. In any case, lateral and vertical dimensions stored in the database for a given feature may include a safe zone extending beyond the actual physical dimensions of the feature.
A further embodiment enables the intervention of remote personnel. For example, in this embodiment, a remote operator may trigger the security mode of the aircraft via an encrypted radio transmission, and similarly may override the feature remotely. A further embodiment allows for remote navigation of the craft by radio once it is in security mode. Such a feature when utilized allows remote personnel to guide the craft during portions of the redirect route, such as landing.